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Finding the Fourth Proportional to 782.90, 1,080.43 and 428.80

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Solution

The fourth proportional to 782.90, 1,080.43 and 428.80 is: 591.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    782.90 : 1,080.43 = 428.80 : x
  2. Step 2: Convert to fraction form
    782.90/1,080.43 = 428.80/x
  3. Step 3: Cross multiply
    782.90x = 1,080.43 × 428.80
  4. Step 4: Simplify right side
    782.90x = 463,290.88
  5. Step 5: Solve for x
    x = 463,290.88/782.90
  6. Step 6: Final answer
    x = 591.76

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.